Research / Constructs / Mermaid diagrams
Mermaid diagrams in five publishing editors
One Markdown fixture, five real publishing editors, tested 2026-08-24. For mermaid diagrams the observed result was untested in LinkedIn; a manual step in X; degraded in WordPress, Substack, and Beehiiv. Every row below is a rule with its own page and its own dated record.
Matches mermaid. Fixture markdown-portability-test-v1. Tested 2026-08-24. How these tests are run.
What happens, per destination
| Destination | What happens | Result | Severity | Rule | Confidence | Last tested |
|---|---|---|---|---|---|---|
| Math, Mermaid, Obsidian syntax, raw HTML, and heading anchors are not live-verified on LinkedIn. | Unknown | Evidence gap | LI-SPECIAL-01 | Unknown | 2026-08-24 | |
| X | Math, Mermaid, Obsidian syntax, and raw HTML are resolved to readable text or a media task. | Manual step | Action | X-SPECIAL-01 | Verified | 2026-08-24 |
| WordPress | Mermaid stays as source code; no diagram renders. | Degraded | Review | WP-MERMAID-01 | Verified | 2026-08-24 |
| Substack | Mermaid stays as source code; no diagram renders. | Degraded | Review | SUB-MERMAID-01 | Verified | 2026-08-24 |
| Beehiiv | Mermaid stays as source code; no diagram renders. | Degraded | Review | BEE-MERMAID-01 | Verified | 2026-08-24 |
Manual steps this creates
- LinkedIn: Check this part of the output yourself before posting. (The focused standard-post test did not isolate these constructs, so no reliable claim exists yet.)
- X: Check each one reads correctly, or attach it as an image. (The composer has no control for any of these and the focused test did not isolate each one.)
- WordPress: Export the diagram as an image and keep a text summary. (Both tested modes showed the fence as a code block.)
- Substack: Export the diagram as an image and keep a text summary. (The source survived as a code block but did not render as a diagram.)
- Beehiiv: Export the diagram as an image and add a text summary. (The tested editor showed the fence as a code block.)
Limits of what was tested
- Each result describes the surface named beside it, on the date named beside it, and nothing wider.
- A result marked unknown means no dated test covers it. It is not a prediction.
- Rendering is not the same across platform versions, themes, plugins, or email clients.
Prepare a draft
- Check your own draft against all five destinations
- Markdown to WordPress, handoff mode: gutenberg paste
- Markdown to Substack, handoff mode: rich html clipboard
- Markdown to Beehiiv, handoff mode: clean markdown paste
- Markdown to X, handoff mode: plain text
- Markdown to LinkedIn, handoff mode: plain text
Related
- The 5 rules behind this page:
BEE-MERMAID-01,LI-SPECIAL-01,SUB-MERMAID-01,WP-MERMAID-01,X-SPECIAL-01 - Every construct, side by side
- The full five-destination matrix